Federalism is a theory of balance. The American system disperses power over fifty states, some much larger number of localities and the federal government. The idea of federalism originally referred to a push for more centralized power, when the Articles of Confederation left too much to the states with too little national cohesion, but the emphasis has changed over the years to areas where the states should retain some degree of sovereignty. Federalism means dual sovereignty, and the push and pull between the two is what creates the balance. The tug of war is the point.

That tug of war is currently in play in cases in Florida and California, as those states debate whether it’s the state or federal sovereign who has the final say on whether undocumented immigrants can practice law.

The question at hand in Florida and California deals with two young men who overstayed their U.S. travel visas. Sergio Garcia came to California from Mexico and remained in the United States illegally at the age of two, returned to Mexico at age nine, and then crossed back into the United States at age 17. Jose Manuel Godinez-Samperio, also from Mexico, overstayed his visa in Florida at age nine. Neither is violating any criminal law by remaining in the United States, but employers are prohibited from hiring either so long as they are undocumented.

Both Garcia and Godinez-Samperio attended public schools, which the federal government requires states to provide to illegal immigrants through grade 12 (and mandates that all children, including immigrants, attend to a certain age). Both then attended public college and law schools. States have discretion over whether they provide public scholarship support within their borders. Some California public colleges offer scholarships to undocumented immigrants, and the Florida Legislature has considered a bill that would grant in-state tuition to non-naturalized immigrants born in the United States, regardless of their parents’ immigration status.

The federal government has moved to block both young men’s bar applications on the theory that it is illegal for them to hold employment, and so no public dollars should support them with professional licensure. Federal law codifies this in 8 U.S.C. § 1621, which prohibits states from issuing a law license to an “unlawfully present alien,” because federal law limits categories of aliens who may receive a professional license that is “provided…by appropriated funds of a state.”

Much ink has been spilled over this country’s ill-conceived immigration patchwork. It is difficult to reconcile any policy that casts out ambitious individuals eager to contribute and to serve. It is more difficult still to consider an understanding of human nature that would imagine “self deportation” by a person whose parents risked a great deal to raise him in a safe place from age two, whose entire civic educated was provided by American public schools, and who has worked even harder to finish college, law school and the moral and intellectual requirements of the bar exam in order to give back to this community. When these are the federal government’s expectations, of course states dealing with large undocumented populations would clash with the feds on enforcement.

Enforcement is what makes immigration such an interesting discussion ground for federalism. The Privileges and Immunities clause of the U.S. Constitution guarantees that the citizens of each state are entitled to the privileges and immunities of citizens in all states, so it makes sense that immigration policy would come from the federal government. But enforcement is an entirely different animal.

Florida and California have two of the highest immigrant populations in the U.S.—19 percent and 27 percent, respectively. That they are only now considering the question of licensing aliens illustrates just how complicated our immigration laws have become.

Under Article I, Section 8 of the Constitution, only the federal government can “establish an uniform Rule of Naturalization.” This is the only time the Constitution mentions immigration. The national immigration policy must be uniform, but it wasn’t until the late 19th century that the federal government actually passed any uniform immigration laws.

Before that, states dealt with immigrants arriving directly on their shores. Between 1790 and 1820, immigrants entered the United States at a rate of about 100,000 individuals per year. It was in the 1830s that immigrants began arriving in droves, with about 500,000 entering the country in the 1830s, 1.5 million in the 1840s and almost 3 million in the 1850s. In the early days, all were welcome save three categories of individuals universally barred from naturalizing as American citizens: criminals, paupers and people suffering from contagious diseases.

In 1875, both the Supreme Court and Congress moved to centralize immigration with the federal government. That year, SCOTUS noted: “The laws which govern the right to land passengers in the United States from other countries ought to be the same in New York, Boston, New Orleans and San Francisco,” and struck down state immigration taxes as unconstitutional on other grounds. Over the next decade, Congress passed a series of statutes limiting who could immigrate to the United States.

Since then, federal immigration policies have waxed and waned, depending largely on the number of immigrants entering the country at any given time, and the countries from which they are emigrating. Periods of stability and economic boom in the United States are predictably linked to periods of high immigration. When many immigrants enter the country, immigration laws tend to expand. For an exhaustive discussion of the history of how federalism and immigration interact, see this excellent piece by Vincent J. Cannato.

Regardless of how welcoming or restrictive our immigration policy has been, the question of enforcement remains unsettled. As recently as this summer, the Supreme Court examined the question of federalism and immigration enforcement in Arizona v. United States.

That case dealt with an Arizona statute attempting to solve that state’s problems with undocumented immigrants, when Arizona felt that federal officers were not handling the issue sufficiently. S.B. 1070 attempted to assert Arizona’s dominion over the enforcement process, requiring state police officers to enforce federal immigration law by going so far as to request identification from anyone who looks or sounds like they might be an illegal immigrant.

S.B. 1070 is bad policy for a number of reasons. But it is the perfect illustration of dual sovereignty. While the federal government is charged with creating a uniform rule of naturalization, it is citizens in—and sovereignties of—the several states that deal with consequences of federal policy. There are few better examples of the importance of states’ rights than realizing that lawmakers in Washington, D.C. have much less incentive to enforce immigration laws in Arizona when those immigrants are two thousand miles away.

Under the Arizona holding, state sovereignty does not constitute a special right to exclude undocumented immigrants from their borders. But what about how immigrants are treated while physically present in the United States?

Ironically, states have an enormous amount of discretion regarding what privileges they may grant to immigrants (but, under Arizona v. U.S., little discretion over whether they may exclude immigrants from their borders, the most traditional sovereign role). The Supreme Court has made clear that equal protection is not limited to U.S. citizens. In Plyer v. Doe, the Supreme Court referred to language used by the congressional committee that drafted the 14th Amendment:

The last two clauses of the first section of the amendment disable a State from depriving not merely a citizen of the United States, but any person, whoever he may be, of life, liberty, or property without due process of law, or from denying to him the equal protection of the laws of the State. This abolishes all class legislation in the States and does away with the injustice of subjecting one caste of persons to a code not applicable to another. . . . It [the 14th Amendment] will, if adopted by the States, forever disable every one of them from passing laws trenching upon those fundamental rights and privileges which pertain to citizens of the United States, and to all persons who may happen to be within their jurisdiction.

It is silly to exclude Sergio Garcia and Jose Manuel Godinez-Samperio from their respective state bars. The federal ban on employing illegal immigrants should not extend to practicing law, which is more like a private contract than the kind of steady employment the federal ban contemplates. Parents from struggling nations will not stop bringing their children to the United States, and federal law mandates that those children attend school. It makes little sense to discourage kids from striving for success.

The federal statute barring states from granting immigrants professional licenses leaves room for states to pass laws to the contrary. States have an opportunity here to consider how they want this scenario to go, and federalism is the tool that allows that. Last summer, we got to see the Supreme Court rule on states’ right to exclude. Watching states decide how much they choose to include will be just as interesting.